包扎及合缝工艺对多层绝热性能的影响

Study on influence of wrapping and seaming techniques on thermal performance of multi-layer insulation

利用静态液氮蒸发量热法测试了4种材料包覆工艺方案下的多层绝热结构低温绝热性能,探究了包扎工艺和合缝工艺耦合作用对多层绝热性能的影响。结果表明:采用贝壳式包扎更有利于绝热性能的提升;对比其它合缝工艺,插接式合缝避免了不同反射层间的干涉,实现了同层等温,因而绝热效果最佳;采用贝壳式包扎、插接式合缝的20反射层多层绝热结构的性能最优,其热流密度为1.840 W/m^(2),表观导热系数为6.699×10^(-5)W/(m·K);采用螺旋式包扎、搭接回折式合缝的20反射层多层绝热结构的性能最差,其热流密度和表观导热系数分别为3.775 W/m^(2)、1.266×10^(-4)W/(m·K)。包扎及合缝工艺对多层绝热性能影响显著,应按实际需求对材料的包覆工艺进行合理有效选择。

Wrapping and seaming techniques act as factors influencing the insulation perform-ance.The cryogenic insulation performance of MLIs under four different material wrapping ar-rangements was investigated using the static liquid nitrogen boil-off calorimetry.This study exam-ined the combined effects of wrapping and seaming techniques on the thermal performance of these MLIs.Results demonstrated that the clamshell-wrapped approach significantly benefited the en-hancement of insulation performance.Compared with other seaming techniques,the layer-by-layer interleaved seams prevented interference among distinct reflectors,facilitating isothermal condi-tions within the same layer and resulting in an exemplary insulation effect.The MLI configuration comprising 20 reflectors,utilizing both a clamshell-wrapped approach and layer-by-layer inter-leaved seams,exhibited superior performance,with a heat flux of 1.840 W/m^(2) and an apparent thermal conductivity of 6.699×10^(-5) W/(m·K).Conversely,the MLI configuration with 20 re-flectors employing a spiral-wrapped approach coupled with overlapped and fold-over seams showed suboptimal performance,with a heat flux of 3.775 W/m^(2) and an apparent thermal conductivity of 1.266×10^(-4) W/(m·K).The choice of wrapping and seaming techniques markedly affects the efficacy of MLIs;hence,it should be judiciously and effectively selected and applied in accord-ance with specific requirements.